/*
 * Copyright (c) 2016-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 */
#include <gtest/gtest.h>

#include <memory>

#include "utils/Buffer.h"
#include "utils/Range.h"

using namespace pzstd;

namespace {
void deleter(const unsigned char* buf) {
    delete[] buf;
}
}  // namespace

TEST(Buffer, Constructors) {
    Buffer empty;
    EXPECT_TRUE(empty.empty());
    EXPECT_EQ(0, empty.size());

    Buffer sized(5);
    EXPECT_FALSE(sized.empty());
    EXPECT_EQ(5, sized.size());

    Buffer moved(std::move(sized));
    EXPECT_FALSE(sized.empty());
    EXPECT_EQ(5, sized.size());

    Buffer assigned;
    assigned = std::move(moved);
    EXPECT_FALSE(sized.empty());
    EXPECT_EQ(5, sized.size());
}

TEST(Buffer, BufferManagement) {
    std::shared_ptr<unsigned char> buf(new unsigned char[10], deleter);
    {
        Buffer acquired(buf, MutableByteRange(buf.get(), buf.get() + 10));
        EXPECT_EQ(2, buf.use_count());
        Buffer moved(std::move(acquired));
        EXPECT_EQ(2, buf.use_count());
        Buffer assigned;
        assigned = std::move(moved);
        EXPECT_EQ(2, buf.use_count());

        Buffer split = assigned.splitAt(5);
        EXPECT_EQ(3, buf.use_count());

        split.advance(1);
        assigned.subtract(1);
        EXPECT_EQ(3, buf.use_count());
    }
    EXPECT_EQ(1, buf.use_count());
}

TEST(Buffer, Modifiers) {
    Buffer buf(10);
    {
        unsigned char i = 0;
        for (auto& byte : buf.range()) {
            byte = i++;
        }
    }

    auto prefix = buf.splitAt(2);

    ASSERT_EQ(2, prefix.size());
    EXPECT_EQ(0, *prefix.data());

    ASSERT_EQ(8, buf.size());
    EXPECT_EQ(2, *buf.data());

    buf.advance(2);
    EXPECT_EQ(4, *buf.data());

    EXPECT_EQ(9, *(buf.range().end() - 1));

    buf.subtract(2);
    EXPECT_EQ(7, *(buf.range().end() - 1));

    EXPECT_EQ(4, buf.size());
}
